Repairing and/or remanufacturing of a toner cartridge generally involve four main stages: (1) disassembly and cleaning, (2) assembly and replacement of defective parts; (3) refilling the cartridge with toner; and, (4) printing from the cartridge after it has been assembled (hereinafter referred to as post-printing).
After the toner cartridge is remanufactured and before the cartridge is shipped, typically the cartridge it tested to verify that all of the applicable components are working properly. This test is generally called a “post-print” of the toner cartridge. The most common way to achieve this is to actually use the cartridge to conduct a printing operation after it has been repaired or remanufactured. As the toner cartridge is printing pages, the printed pages are inspected to verify their quality and proper operation of the cartridge. This post-print test will show if any of the components need to be re-worked and/or changed before shipping the toner cartridge to the end user.
Most types of cartridges contain a seal that prevents the toner from leaking during shipping. In those instances, one cannot conduct a post print test since the toner in the toner hopper does not have accessibility to the developing section. To conduct this post-print test after the cartridge has been assembled, a small amount of toner, approximately 10 to 20 grams, is placed on the developing roller so the post-print procedure can be accomplished. After the post-print toner has been applied to the developing roller section, the toner cartridge assembly will be completed. The completed cartridge is then placed into an appropriate printer. Several standard test pages are printed, and these pages contain several, different graphic images that provide indications of the general condition of the cartridge. If any problem is revealed from the images shown on the printed graphics on the test pages, then the cartridge is removed and re-worked to fix or eliminate each of such problems. Although this test does use several grams of toner, it typically does not consume all of the toner that has been placed in the developing section of the cartridge.
During the post-test, an indication on the printing pages that most of the post-test toner has been used occurs when the pages start to show toner starvation. With magnetic toner developing systems an indication of toner starvation occurs when the post-test printing pages start to print white pages only. Nevertheless, these cartridges typically contain some residual toner, and this residual toner can be the source of the leakage or “sweating” problem described above. It has been discovered that this leakage or sweating problem is relatively less severe for cartridges containing magnetic toner developing systems, and relatively more severe or pronounced for cartridges containing non-magnetic toner developing systems, which are usually found in cartridges used in full-color printers containing colored toner.
The non magnetic toner developing system cartridges that have developer rollers that are not magnetic present a more serious problem simply because of that fact. A magnetic roller will tend to hold on to most of the post-print toner by using a magnetic force, but a non-magnetic roller, once in the printer, will attract the toner using an electro-static charge. Once the cartridge is taken out of the printer, there is no charge applied to the roller, thus there is no electro-static forces between the roller and the toner causing the toner to fall off the roller. It has been discovered that the post-test toner in cartridges with non-magnetic rollers will tend to leak/sweat out during the shipping process. Another major problem with the non-magnetic toner system is that since the toner doesn't hold to the developer roller once the cartridge is not in the printer, there is a chance that the excess will accumulate on other components, potentially causing permanent printing defects. Two major components that exhibit this problem are the PCR (Primary Charge Roller) and the OPC (Optical Photo Conductor).